1. Field of the Invention
The invention relates to a torsion damping device, especially a double damping flywheel forming a torque transmission device for a motor vehicle, of the type comprising two coaxial masses mounted movably in relation to one another in opposition to resilient means and friction means.
2. Description of the Prior Art
A torsion damping device is known which comprises a first mass intended to be fixed to a driving shaft, such as for example the crankshaft of the engine of a motor vehicle, and a second mass forming a reaction plate for a friction clutch, where the friction means are provided in a strengthening bearing part which extends between the first mass and the second mass. For this purpose, the bearing part comprises an axial shoulder provided with teeth which can be edge-formed, which serves to house a friction washer and a meshing washer biased for example by a Belleville washer, the teeth being edge-formed by means of a matrix of tools once the washers are in position. One may consider making the teeth thinner in relation to the shoulder and extending them in the shoulder by cut-outs so that the bending operation is facilitated.
However, the result after bending is not entirely satisfactory: the teeth are often twisted. Moreover, if the number of washers is increased in order to modulate the friction characteristics, the axial dimension of the teeth is lengthened, making twisting even more probable.
The object of the invention is in particular to remove this drawback.